A wet month with record breaking rainfall

Area averaged across the state, and based on records since 1900,
Queensland had its wettest September on record. The state wide average rainfall
was 75.98 mm (breaking the previous record of 70.58 mm set in 1906), well above the
long term average of 12.68 mm.

Rainfall

A series of surface troughs swept eastwards across the state in
September, some combining with upper level troughs to generate cloud
and rainbands that extended from the north west to the south east of
Queensland during the month.

Heavy rainfalls occurred around the 5th and 6th of September from
a thundery rainband which extended from the north west and across
central districts on the 5th, and then over the south east of the state
by the 6th. This rainband also generated locally moderate to heavy
falls in parts of the Central West, Central Highlands, Capricornia,
Wide Bay and Burnett and northern Darling Downs districts.

More heavy rain occurred on the 19th as an upper trough situated
over Central Australia moved eastwards and produced a cloud band with
rain areas over most of Queensland. In addition, a surface trough over
the central interior produced locally heavy rain and storms, in
particular over the Central Highlands, Central Coast and Northern
Tropical Coast.

The same upper trough was near stationary and situated over
northern South Australia and New South Wales by the 23rd, maintaining
cloud and patchy rain areas over Central Queensland from the
23rd to the 26th. Another surface trough extended across inland
Queensland on the 25th and rainfalls were concentrated around a
thundery
rainband about the state's interior. Some
significant falls also occurred in the humid, unstable air mass to the
east of the surface trough. On the 27th and 28th, scattered showers
and thunderstorms occurred over northern and eastern Queensland, more
isolated near the east coast, as the inland trough remained near
stationary. By the 29th the surface trough was moving north along the
southern Queensland coast and showers and thunderstorms occurred over
far northern and eastern Queensland, with locally heavy falls. On the
30th the trough moved off the east Queensland coast and following the
trough, a strengthening ridge extended along the east Queensland
coast from a high moving east across southeast Australia with cooler
southeasterly winds and isolated showers.

The highest daily rainfall total was 164.8mm at Mackay Aero on the 20th
of September, followed by 148.6 mm at Innisfail on the 29th,
followed by 145.4 mm at Proserpine Airport on the 20th.
Forty-four stations in Queensland with twenty five or more years of record had their highest September daily rainfall on record.

The highest monthly rainfall total was 612.8 mm at Bellenden Ker Top Station, followed by 378.6 mm at Orion, followed by
324.6 mm at Springsure Comet St.
Eighty-seven stations with twenty five or more years of record had their highest total September rainfall on record.

Temperature

Area averaged across the state, the mean maximum temperature for
September was 28.44 °C, where
the long term average is 28.67 °C. Maximum temperatures were
slightly below the long term average due to the persistent cloud bands
that developed during the month.

Also as a result of the cloud bands, the area averaged mean minimum
temperature for the state during September was 14.83 °C, well above the long term average of 11.91
°C and the second highest on record, based on figures since 1950
(the highest on record was 15.32 °C in September 1998).

Maximum temperature

Mean maximum temperatures for September were generally below average
south of about 21 °C, by up to 5 °C in the western Channel
Country, and above average to the north by between 1 and 3 °C.
Kowanyama Airport and Willis Island both recorded their highest September mean daily maximum temperature on record.

The warmest days on average were 37.0 °C at Kowanyama Airport, followed by 35.9 °C at Normanton Airport, followed by 35.6 °C at Croydon Township.

The hottest day was 40.3 °C at Century Mine on the 13th, followed by 39.3 °C at Century Mine on the 14th, followed by 39.2 °C at Julia Creek Airport on the 13th.

A number of stations in the Channel Country, Central West and Maranoa and Warrego recorded their coldest September day (lowest maximum temperature) on record
between the 17th and 19th of the month due to cloud cover and rain
areas. Daytime maxima were generally well below average in
southern districts, with many centres between 10 and 16 °C
below their September averages.

The coldest day was 11.3 °C at Roma Airport on the 19th, followed by 11.4 °C at both Injune Post Office and Mitchell Post Office on the 19th, followed by 11.7 °C at Charleville Aero on the 19th.

The coolest days on average were 18.1 °C at Applethorpe, followed by 18.8 °C at Stanthorpe Leslie Parade, followed by 20.2 °C at Toowoomba Airport.

27.0 °C at Horn Island on the 22nd
27.0 °C at Horn Island on the 27th
26.9 °C at Horn Island on the 23rd
26.8 °C at Coconut Island on the 6th
26.8 °C at Normanton Airport on the 11th
26.8 °C at Horn Island on the 25th

Notes

A Monthly Climate Summary is prepared to list the main features of
the weather in Queensland using the most timely and accurate
information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at
10 am on Friday 1 October 2010.
Some checks have been made on the data, but it is possible that results will change
as new information becomes available.

Averages are long-term means based on observations from
all available years of record, which vary widely from site to site.
They are not shown for sites with less than 9 years of record, as they cannot then be calculated reliably.
The median
is sometimes more representative than the
mean
of long-term average rain.

The Rank indicates how rainfall this time compares with the climate record for the site,
based on the
decile ranking
(very low rainfall is in decile 1, low in decile 2 or 3,
average in decile 4 to 7, high in decile 8 or 9
and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a
percentage of the long-term mean.

* The data for September 2010 at this site has been compared to another nearby site with a longer record.